Nitrate Removal from Groundwater by Heterotrophic and Electro-Autotrophic Denitrification

A heterotrophic and autotrophic denitrification (HAD) system shows satisfactory performance for groundwater with nitrate contamination. In this study, an HAD combining solid-phase electrochemical hydrogen (SHD-EHD) was developed the treatment of nitrate-contaminated groundwater, in which polycaprolactone (PCL) used as carbon source to enhance removal prevent secondary pollution (EHD) system. The performance, microbial community structure nitrogen metabolism were investigated. results showed that a high rate 99.04% achieved influent concentration 40 mg/L, current mA hydraulic retention time (HRT) 4 h. By comparing EHD system, it found PCL promoted complete reduced accumulation NO2?-N. Analysis identified key denitrifying bacteria: Dechloromonas, Thauera Hydrogenophaga. comparison communities from SHD-EHD (SHD) demonstrated electrical stimulation abundance dominant bacteria electroactive bacteria. metabolic pathway revealed conversion NO N2O rate-limiting step overall pathway. study great potential removal.